The present invention generally relates to the field of portable electronic printers, and particularly to an electronic printer for utilization with a portable hand-held computer.
Portable hand-held computers are typically utilized for data collection and management in the modern computerized business world. For example, commercial transactions for the sale of goods may be stored in a portable hand-held computer that is carried by delivery personnel to a customer""s place of business. After the delivery driver enters execution of the transaction into the hand-held computer, an invoice verifying the date, time and contents of the delivery is desired. The invoice may be conveniently printed with a portable printer to which the delivery driver may connect the hand-held computer.
The usefulness of portable printers has been enhanced by efforts in reducing the size and modularity of printers when compared to their respective forerunners. Also, minimization of tasks may further the utility of portable printers by route service people in operating the printers.
It is highly desirable to increase the efficiency and productivity of the user of the printer by improving the speed at which the printer operates. It would therefore be advantageous to provide a printer having an improved control system for controlling the operation of the printer motor controls and printing head such that the effective printing time for a given print job is reduced.
Furthermore, it is highly desirable that a portable printing system is adaptable to a variety of environments or applications. Thus, it would be desirable to provide a printer having a memory and file system that allows for updating program code and data such as printer fonts and character systems. The printer would therefore be capable of being adapted to a variety of applications for use with a multiplicity of countries or languages. An advanced printer control system would additionally provide advanced control features such as the ability to cancel printing jobs with a serial interface without having to first print the entire print buffer, or to verify the integrity of files downloaded into an updateable file system, among other advantages.
It is also highly desirable that a printer system be able to adjust its print settings and print time so as to adequately function in different environments or with different print media. For instance, in extremely cold environments, it is desirable to increase the impact force at which a contact printer strikes the paper when printing. In addition, when thick print media is used (e.g. five part carbon copy paper as opposed to three part carbon copy paper) it is likewise desirable to increase the impact force at which a contact printer strikes the print media. Environmental conditions such as temperature, barometric pressure, or atmospheric pressure may also affect other print settings of a print system. Thus, in a laser printer, a contact printer or an ink jet printer, it may be desirable to increase the temperature of operation of the printer when the print system is used in extreme environmental conditions.
The present invention is directed to a control system for a portable electronic printer. The control system of the present invention implements, among other things, a method for performing a self-test of the hardware of a portable electronic printer, a method for monitoring the hardware of a portable electronic printer for a failure, a method for diagnosing a portable electronic printer, a method for booting a portable electronic printer having both volatile and non-volatile memory, a method for controlling the printing of data received from a serial transmission line whereby printing may be canceled, a method for controlling a printing system such that code or data in the printing system may be updated, a method of verifying a downloaded file in a printing system, a method for determining a communications protocol in a printing system, and a method for controlling communications in a printing system during a diagnostic routine.